"When the original Vertex and Agility product lines were introduced, we were told that the Vertex had a specific BOM (Build of Materials) list and the Agility had a dynamic BOM. In the end we found the first Vertex to have one set of flash that never changed, but the Agility shipped with three or more different flash configurations. The Agility was sold at a lower price because it used whatever flash was the lowest priced at the time of manufacture. While all who purchased an Agility were rolling the dice as far as what flash was included, some ended up with a drive that was identical to the higher priced Vertex.
When Vertex 2 and Agility 2 hit the market things changed again; Vertex 2 shipped with a higher IOPS programming and Agility 2 was shipped with the lower programming. For the most part this was an acceptable situation, but the BOM was never nailed down for Vertex 2. Eventually OCZ started playing loose and fast with the second series of these SSD products and somewhere along the line in December 2010 Vertex 2 drives started shipping with 25nm flash."